Process for the production of acetone



Patented Sept. 10, 1935 PATENT OFFICE PROCESS FOR THE PRODUCTION OF ACETONE Koloman Roka and Karl Wiesler, Constance, Germany No Drawing. Application May 11, 1933, Serial No. 670,619. In Germany November 14, 1926 17 Claims.

This inventionrelates to the production of acetone from acetylene, and is, in part, a continuation of our earlier application Serial No. 228,- 685, filed October 25, 1927.

Although the preparation of acetone by reacting acetylene (CzHz), and water vapor at high temperatures has been effected, the process has never been satisfactory from a commercial standpoint. The yields of the desired ketone have always been too low to permit that economy which is requisite to a process of satisfactory commercial practicability. Moreover, the catalysts employed in the known processes have always lost their efficacy after a relatively small period of continuous use, thus necessitating the frequent renewal of these contact masses. This has added to the expense of producing the acetone and has deterred manufacturers from utilizing the process com-- mercially. Moreover, the inconvenience of frequently replacing the catalyst in the reaction vessels and the irregularity caused by such replacement have prevented the process from becoming a reliable commercial method for the manufacture of acetone.

Our invention has for one of its objects a process for the production of acetone from acetylene and steam which will result .in yields of the desired ketone in such amounts that the process'can be carried out efiiciently in the commercial manufacture of this chemical compound. Moreover, our process is one which permits continuous production in the large quantities necessary for efiicient factory operation, since the catalytic materials we employ suffer no appreciable decrease in catalytic power regardless of the duration of the reaction period. Another object of our invention is the avoidance of frequent replacement of the contact mass by the use of catalytic mixtures which maintain their activity for practically unlimited periods.

Still another purpose of our novel process is the production of acetone by a procedure which will not be affected by catalytic poisons present in the acetylene and will not require an extremely large excess of water vapor or steam. These features are important because they make possible in our process the use of ordinary acetylene Without the necessity of purifying this gas to a high degree. By reducing the quantity of steam required, the process is carried out with a maximum economy. If it were necessary to free the acetylene from impurities, the cost would be increased to such a degree that the process would be commercially impractical. It is clear, therefore, that in the process disclosed herein, this enormous tone.

expense accompanying prior procedures has been eliminated.

Another object of our process is the reactio of the acetylene and steam at a lower temperature than was formerly usual in this type of re- 5 suits in further important economy of operation.

Our process depends on a principle which we are the first to employ in a reaction of this type. This principle, which involves the adjustmentof the catalyst so as to yield a partial oxygen pres- 15 sure within certain fixed limits, has never before been applied in the commercial production of ace- This method of adjustment will be fully described later on in this specification.

Reference may be made at this time to Austrian 20 Patent No. 88,631 which describes the method which was known prior to the invention of the applicants but which never went into commercial use. The process of this patent requiresthat the acetylene be freed of catalytic poisons and will re- 5 sult in acetone in appreciable amounts only when water vapor is present in forty times the quantity theoretically required for the reaction. Under some conditions a yield of 40% of acetone has been obtained, but this yield is too low to permit 30 the method to be used commercially to any great extent.

The process of the Austrian patent suggests the use of catalysts which are as rich as possible in iron oxide. These are to be obtained by precipitating iron oxide and pressing the precipitated material into lumps. When only small quantities of F8203 are present, as in a catalyst prepared by applying iron oxide to a contact carrier material, the formation of acetone is considerably reduced, the main product consisting of acetaldehyde. For this reason the Austrian patent states that natural iron ores and their lay-products such as clay ironstone (FeCOz), clay, and shale, sparry iron ore, and waste from pyrites may be used as catalysts with the production of acetone in yields from 25 to It is to be noted that the yield is relatively low and that purified acetylene and a large excess of water vapor are essential to success.

The applicants have made thorough studies of 50 the entire problem with a view to improving the process so that yields of acetone approaching the theoretic-a1 may be obtained. As a result of these investigations, thediscovery was made that the activity of the main catalysts employedinthe oxide compounds therein mentioned, could be increased and prolonged to a very considerable extent by the addition of one or more cooperating auxiliary catalysts. Among these auxiliary catalystsmay be mentioned metallic iron, manganese oxide, aluminum oxide, barium carbonate, zinc carbonate; lime, and magnesia. It may be pointed out'that the oarbonates of-barium, calcium,

andzinc are easilyqeduced during the process and yield the oxides of the metals which to gether with the iron oxide constitute the catalytic masses. For this reason the applicants have made further investigations with a view to de-= termining the essential nature of thbcatalytic materials necessary. These studies ledto the following astounding results. 7 We found after considerable experimentation thata mixture of metallic compounds provided 'acatalytic, agent of'unusual stability and activity.

These mixtures of metallic compounds, preferably metal-oxygen compounds, gave very satisfactory results over unusually long periods of time and especially satisfactory results wereobtained when the partial oxygen tension of the mixture was adjusted within certain values as more fully described subsequ ently in this disclosure. While all metallic compounds containing oxygen are suitable, we have found that metal oxides, or salts which yield the oxide of the respective metals under the conditions of the proc- "ess, such as carbonates, acetates, tartrates, or other similar salts will yield the most satisfactory results.

The'prepared catalytic mixture may comprise a heavy metal carrier and a metal-oxygen compound. For this latter compound either an oxide of a heavy metal or an oxide of a light metal orboth may be used. Specifically, a heavy metal;

oxide and a light metal oxide may be employed in conjunction with some type of metal carrier. of course, in place of the oxides, any metaloxygen compound may be used with more or less success, and metal oxygen compounds which yield the oxide under the conditions of the process will be found to give excellent results. Two metal oxides may be admixed to form the catalytic material and the partial oxygen tension of the mixture may or may not be adjusted as hereinafter described. A mixture of aheavy metal-oxide and a light metal oxide, or a heavy metal oxide and a light metal carbonate has been found to constitute a stable and eflicient catalyst. A mixture including a heavy metal-oxide and an-' other heavy metal oxide, or a heavy metal oxide and a heavy metal carbonate is an excellent contact mass. Mixtures of heavy metal oxides and,

a metal or light metal oxides and a metal; or a mixture of a light metal oxide and a heavy metal oxide with a metal carrier have all been tried with success. Other metal oxygen compounds may be used instead of-the oxides in these specific mixtures and the employment of a salt which will yield a metal oxide under the conditions of the process is the full equivalent of the use of the oxide. Mixtures ofthree, four or more metallic oxygen compounds have been tried with very satisfactory results and some examples of processes which employ such catalytic mixtures are more fully described below.

We have made many experiments on a commercial and semi-commercial scale with ironoxygen compounds, such as iron oxide or any compound yielding iron oxide under the conditions of the process in conjunction with a metal, such process of the Austrian specification, the iron as iron, andan auxiliary oxygen-containing catalyst such as manganese oxide, barium carbonate, barium oxide, and similar oxidic'materials. The results have always been very satisfactory. Ad-

vantageous results are often attained by the em- 5 equal success and we do not desire to be limited to any class or group of metals.

When we have referred to heavy metal oxides 20 in the foregoing description we have had in mind the following specific oxidic materials which will be found suitable. The list is merely illustrative of this type of metal-oxygencompound and is by no means to be interpreted as limiting the 25 catalytic materials which may be employed in our process. The roman numeral after each of the metals indicates the group of the periodic table m which the metal is found. These heavy metal oxides are those of the following metals, iron 30 VIII, cobalt VIII, nickel VIII, manganese VII, molybdenum VI, tungsten VI, bismuth V, antimony V, lead IV, tin IV, cadmium II, mercury 11, copper I, and silver I.

Aslight metal oxides, compounds yielding the 35 oxides of any of the following light metals are suggested and will be found suitable. Here again the list is-merely illustrative and not restrictive. The roman numeral again indicates the group of the periodic table in which the metal is clas- 40 sified. These oxides of light metals are sodium II, potassium 1, magnesium II, calcium II, zine II, barium'II, and aluminum III.

It is to-be understood, of course, that compounds which readily yield the metallic oxide 5 I under the conditions-oi the process may be used v in place of the oxide itself, for indeed this amounts to a use of the metallic oxide. Carbonates, nitrates, and acetates are very readily reduced to the oxides and may emciently be em/ 50 'plo'yed in the process. carbonates such as those of zinc, magnesium, barium, and calcium are usually more readily obtained than the oxides and may be readilyused as the equivalent of the metal oxides. some illustrations of the use of nitrates, acetates and carbonates for the purpose of furnishing a metal oxide to the process.

Particular mixtures of certain metallic compounds have been found to yield catalysts of high 60 eiliciency and unusually long life. Thus a mixture of an oxide of manganese such as manganese dioxide and an iron oxide (either FeaO: or F8304) has been found particularly successful in our Process. A mixture of iron oxide and a car- 65 bonate of a heavy metal such as magnesium, lead,

or bismuth may be utilized. Mixture of threeor more oxidie materials such as the oxides of zinc, iron, and manganese, or those of magnesium,

iron, zinc, and manganese, or other combinations have been found very suitable-in the process. Oxidic mixtures and metallic iron, ora single metal oxide and metallic iron (such as an iron reaction pipe) have been found to furnish contact masses of unusual stability and ei'liciency.

The appended examples fumish 55 A fundamental principle which maybe employed in the selection of oxidic mixtures is to admix' the substances so that a partial'pressure of oxygen within the limits of 10- atmospheres and 10- atmospheres will result. While not limited inrange to therange defined by these two partial dissociation values, it will be found that our process yields excellent results within these ranges when the process is carried out at 400 C. or 500 C. with five to ten parts of water vapor to one part of acetylene.

As explained above, it may be advisable under some circumstances to select and arrange the catalysts so that under the conditions of the process an oxygen tension is produced which falls within the-limits given above. This maybe accomplished'in any manner well known to the skilled chemist. For convenience, an explanation of the method and a reference totheliterature is now given in some detail. Partial dissociation values and adjustment of the components of mixtures to attain any given predetermined oxygen tension may be readily carried out in accordance with the following procedure.

The process can perhaps best be explained by the use of a specific example. In one aspect of our process one mole of acetylene and ten moles of steam are caused to react at a temperature of 500 C. in the presence of a catalytic mixture which may be composed of iron oxide with the addition of other suitable metal oxygen compounds. The determination of the oxygen tension naturally resolves itself into two problems, first, the determination of the oxygen tension in the gaseous phase due to the presence of water vapor in the reaction, and second, the determination of the oxygen tension of the solid phase.-

The oxygen tension in the solid phase is due to the presenceof the solid metal oxygen compounds as catalytic materials, and it is the adjustment of this oxygen tension which formsthe practical problem to be solved in these theoretical considerations. s

A. Oxygen tensions in the gaseous phase The reaction occurring in the process of this application is expressed by the fo llowingformula:

' However, in order to obtain satisfactory yields, we have found that two moles of acetylene should preferably be reacted with an excess of water vapor so that for every two moles of acetylene there is present a quantity of steam amounting to twenty moles. When this condition is inserted in the chemical equation, the following equation results:

From this equation it is therefore apparent that if p expresses an oxygen tension' or partial pressure, the following ratio represents the conditions in the reaction vessel:

From considerations of physical chemistry, the value of the constant K is expressed as follows:

The numerical value of this constant can be determined very accurately by the equation given by Siegel, see Zeitschrift fiir Physikalische Chemie, volume 87, page 641 (1914).

For a temperature of 500 C., T is 773 since T represents the absolute temperature for these conditions. K'pi-l o has a numerical value of 3.33 x 10*".

Substituting this value in Equation (4) there results: 7

2 p0,= 'p f Pn =3.33 X l0 (8.5) 0.25 X 10- B. Oliflgen tensions of the solid phase The oxygen tension of the solid phase catalysts may be oomputeddfrom the heat of formation which is given by-qthe Nernst equation. See Treadwells'article, Zeitschrift Electro Chemie, volume 22, page 414 (1916). See also Pollitzer Berechnung der Chem. Afiinitaten nach dem Nernst'schen Warme-Theorem. The equation is as follows:

. In this equation Q represents the heat of formation.

1. In order to ascertain the oxygen tensions of F8203 at difierent temperatures, a knowledge of the heat of formation arising from the reaction:

log p=m -i 1.75 log T+2.8

is necessary. Treadwell has determined that at room temperature Q=90,400 calories.

At 1000 C. Treadwell deduces as a result of his potential measurements that Q=91,000 calories.

If we use the mean y'alue of Treadwells measur'ef ments for the value of Q in the Nernst equation,

we find:

(9) p =l.5Xl0 2. For F6304 the oxygen tension at 500 C. can

be similarly determined. The values result asfol-' lows:

I I 1.2 X 10 4.4 x 10- 1.4 x 10- It will be seen that these measurements do not agree very closely. The variance is the result of use of different values for the heat of formation. The three values for the heat of formation which result in the three different values for of F8304 are those of:

a. Wiihler & Giinther Zeitschrift El. on. 29,25

canbe computed:

cal values will be found in the Physical Chemical Tabellen by Landaldt Biirnstein, vol. 2, page 1405. I

If it should be desired to adjust the oxygen tension to a value of 025x10 atmospheres, as in the process? described in this application, it is at once apparent that this value is attained by the use of a mixture of F820: and FeO, with a lower FeO content than that which corresponds to the FeO content in t e oxide R304. The percentage of FeO in the xture is then ascertained by experimental determination of the oxygen tension of several different mixtures. This experimental determination of the oxygen tension may be done by several methods, one of which, for example, is the method disclosed in the Treadweli article referred to above. This involves determination of the oxidation potential E and by use of the following equation represents the'constant resulting from homogeneous water vapor dissociation, and K represents the constant of the heterogeneous system. By using the Siegei equation the values obtained for the constant are very accurate values. However, by the use of the Nernst equation of approximation, values of sufiiclent accuracy are obtained.

I 4. The heterogeneous CO: values are combined in a similar way with the homogeneous carbon dioxide values, and this permits a computation of the oxygen tensions. Bee K. Hofmann, zeitschrift'fiir El. Ch., 31, 172. (1925).

A few determinations of this kind are sufficient to ascertain the composition of the mixture which will possess the desired oxygen tension. It is believed that it is quite clear how the concentration I of FeO should be changed in the mixture and that the oxygen tension for each mixture containing a certain percentage of FeO can be very readily ascertained.

It is also apparent that this method can be applied not only when using the iron oxide FeO in the mixture, but also when other metallic oxides are admixed. If it is required to diminish the oxygen tension of, for example, FerOs, iron oxide, a metal oxide such as zinc oxide, aluminum oxide,

- calcium oxide, any of the manganese oxides, or

other metal oxygen compounds can be very ,readily substituted for the ferrous oxide.

The particular oxygen tension to be maintained is readily derivable from and is correlated with the degree of dissociation of water vapor as determined by the temperature and dilution of the acetylene under the conditions at whichour procis carried out. It will be found that adjustment of thepartial oxygen tensions within the sults. It has been frequently found advantarange specified results in catalysts of particularly long life.

Our process is advantageously carried out with more than four parts by volume of water vapor or steam to one part by volume of acetylene. When five to ten parts by volume of water vapor to one part of acetylene are employed with catalysts which have been adjusted to a predetermined oxygen tension the results are excellent. An excess above fifteen parts of water vapor or steam to one part of acetylene should, in general, be avoided, as such an excess is unnecessary and uneconomical.

- The temperature at which our process is carried out with highest efficiency is somewhere between 250 C. and 750 C. In general main operating temperatures. between 350 C. and 600 C-., and preferably within the range of 450. C. to 550 C. will be found to give most satisfactory re geous to start the process at a comparatively low temperature and then increase the temperature. either gradually or in stages to a higher value. In this way it is possible to maintain the oxygen tension continually within the limits satisfactory for the reaction.

Specific examples of our process are appended hereto, and further details of'the conditions of operation will be found therein. It is to be understood, of course, that these operating conditions are merely illustrative and our invention is by no means limited to the precise process as defined in these examples.

It may be mentioned here that ores have in general been found unsuitable for catalytic masses, although they may frequently form an initial material from which a satisfactory catalyst may be produced. The ore disclosed as suit-' able in the Austrian patent referred to has been found to yield unsatisfactory and uncertain re- 0 sults. When the process is carried out as described in this patent, the catalyst was, found to have lost its emciency after use amounting 'to three days. The catalytic masses disclosed in this specification as our invention have been 45 found to be of undiminished activity after thirty days or more of continuous use.

As examples of our novel process, -I submit the following:

. Example! superficially oxidized iron shavings were heat ed in an iron pipe to about 500 C. to form the catalyst. Over the catalytic agent thus result ing, a mixture of acetylene and water vapor in the molecular proportion of. 1:10 was passed. The vapors issuing from the heated reaction pipe were cooled and resulted in a dilute solution of acetone, the yield of this ketone amounting to 83% of thetheoretical quantity as calcug lated from the acetylene employed in the process.

The non-condensable fraction contained 7.6% by-volume of unchanged acetylene. The yield.

. of the desired ketone; acetone,'was indeed very satisfactory, since quantitatively it amounted to 94% of the theoretical, based on the quantity of acetylene entering into the reaction.

rza puu" Iron shavings were coated with iron oxide and manganese dioxide and introduced into a reaction pipe. Over thiscatalytic material'a mixture of vapor, by volume, were passed at 475 :C. The

vapors issuing from the reaction pipe were con- Example III Iron shavings were provided with a superficial coating of iron oxide and barium carbonate, and

A mixture of acetylene and water vapor in the ratio of one part CsHz to ten parts of water, by volume, was passed through the reaction pipe at a temperature of 470 C. Upon condensation of the issuing vapors, acetone in the amount of 90% of the maximum yield possible, calculated on the 7 quantity of acetylene used,'was obtained.

Example IV Naturally occurring manganese dioxide was impregnated with zinc acetate in the amount of 25% of its weight. The manganese dioxide, thus impregnated was subjected to a current of nitrogen at 600 C. for the purpose of decomposing the material. Over the oxidic mixture thus produced, a mixture of acetylene and steam was led. The process, which was carried out at 420 C., was regulated so that a mixture of 9.9 liters of acetylene and 119 grams of steam, per liter of catalyst, was conducted over the catalytic oxidic material every hour.

After four hours a yield of 75.3% of acetone was obtained. The quantity of acetylene which did not enter into the reaction and was regained unchanged amounted to 9.7%, while 8.8% of the acetylene supplied was converted to carbon dioxide, as a result of complete combustion.

Example V Granular pumice stone was impregnated with zinc acetate, iron nitrate, and manganese acetate. The materials were employed in the following proportions, 800 grams of pumice stone requires 135 grams of zinc acetate, 148 grams of iron nitrate and 15 grams of manganese acetate. The

-pumice stone, thus impregnated, constituted the Example VI The catalyst was prepared by impregnating 920 grams of granular magnesite (MgCOs) with a concentrated solution containing 125 grams of iron nitrate. The magnesite was then heated and during the process it was impregnated with a second solution containing 68 grams of zinc acetate, 125 grams of iron nitrate, 7.5,gramsof manganese acetate and 10 grams of magnesium acetate. This resulted in the precipitation of the respective metallic hydroxides, whereupon the catalytic material was filtered off and dried.

Over this contact mass, acetylene and steam were passed, at the rate of 11.3 liters of acetylene, and 136 gramsof steam per liter of catalyst, per

form from the issuing vapors was 8.3% of the 5 total, which 5.9% of the acetylene supplied to the process was lost by conversion to carbon dioxide.

Example VII The catalyst was prepared by impregnating oxidized iron sponge with a solution containing 90 grams of zinc acetate for every kilogram of iron sponge. The process was carried out by conducting a mixture of acetylene and steam at the rate of 10.8 liters of acetylene and 138 grams of steam per liter of catalyst, per hour, over the contact mass at. a temperature of 425 C. The process was continued for 218 hours. A yield of 83.7% of acetone was obtained, calculated on the basis of the acetylene supplied to the reaction. 20 The issuing gases showed 4.2% of carbon dioxide and 9.1% ofunreacted acetylene.

Example VIII Example IX 35 Oxidized iron sponge was impregnated with zinc acetate, iron'nitrate, and manganese acetate until the metals impregnated, calculated as the respective metal oxides, amounted to 4.2% of the catalyst. The metals zinc, iron and manganese were present in the ratio, 411.5:1. Over this catalyst a mixture of acetylene and steam was conducted at a temperature of 440 C. The mixture consisted of 9.5 liters of. acetylene and 114 4r grams of steam per liter of catalyst per hour. At the end of 284 hours, a yield of acetone of 89.7% of the theoretical, based on the quantity of acetylene supplied, had been obtained. The quantity of acetylene passing through unchanged Was.6.3% and 1.6% of carbon dioxide was present M in the issuing vapors.

Easample X Over a catalytic mass prepared as in Example IX, a mixture of acetylene and steam was passed at 440 C. The mixture contained 9.5 liters 'of acetylene and 114 grams of steam per liter of catalyst per hour. At the end of four hours the yield of acetone was 84.8%, based on the quantity of acetylene used in the reaction. The unchanged acetylene was 4.6% of the total, and the issuing gases contained carbon dioxide corresponding to 0.24% of the acetylene. This represented a loss of. acetylene due to too complete a combustion.

Emafnple -XI Over a catalyst "prepared as in Example IX, a mixture of acetylene and steam was conducted at a temperature of 450 C. 19.1 liters of acetylene and 230 grams of steam were led over the catalyst every hour for every liter of the contact mass. After 76 hours, a yield of 85% acetone was obtained, calculated on the quantity of acetylene employed. 10% of the acetylene passed through 7 unchanged, while the waste products included 3.6% of carbon dioxide.

Example XII Oxidized iron sponge material was impregnated with zinc acetate, iron nitrate and magnesium acetate until the resulting metallic oxides amounted to 4.3% of the weight of the catalyst. The three metals added by impregnation were 10 present in the ratio 12:1.3z1. Over this catalyst a mixture of acetylene and steam was conducted at 440 C. "The reacting mixture was passed over Over a catalyst prepared as in Example XII, a

25 mixture of acetylene and steam was passed at a temperature of 440 C. The acetylene and steam mixture was fed at a rate of 9.8 liters of acetylene light metal, the said catalyst having the partial pressure of oxygen within the range of 10 to 10- atmospheres.

6. A process for the production of acetone which comprises passing a gaseous mixture of acetylene and steam over a catalyst comprising essentially a plurality of oxides of heavy metals, the said catalyst having the partial pressure of oxygen within the range of 10- to 10' atmospheres. I 10 '7. A process for the production of acetone. which comprises passing a gaseous mixture of acetylene and steamover a catalyst comprised essentially of iron oxide and a heavy metal carbonate, the said catalyst having the partial pressure of oxygen within the range of 10- to 10- and 118 grams of steam per liter of catalyst per i hour. At the 'end of four hours, the acetone yield 30 was 93.7% of the quantity of acetylene supplied.

The uncon'verte'd acetylene was 5.3% of the total, and 1.2% of 02H: was lost as carbon dioxide.

Having thus described the invention, what we claim as new and desire to secure by Letters Pat- 35 ent of 'theUnited States is:

1. A process for the production of acetone which comprises passing a gaseous mixture oi acetylene and steam over a' catalyst comprising essentially at least one substance selected from 40 the group consisting of metal oxides and metal oxygen compounds which readily yield the oxide under the reaction conditions, the said catalyst having the partial pressure of oxygen within the range of 10 to '10- atmospheres.

2. A process for the production of acetone which comprises passing a. gaseous mixture of acetylene and steam 'in approximately the pro- I portions, by volume, of one part of acetylene to 5 to 15 parts of steam over a catalyst comprising 50 essentially at least one substance selected'from the group consisting oi'metal oxides and metal oxygen compounds which readily yield the oxide v under the reaction conditions, the said catalyst having the-partial 55 rangeof '10 to 10- atmospheres.

' 3. A process for the production of acetone which compri s passing a gaseous mixture or acetylene andfi portions, by volume, of one part of acetylene to 5 to 15 parts of steam over a catalystcomprising essentially a metal oxide. the temperature or the reaction being maintained between 250 C. and 750 C., the said catalyst having the partial pres- 55 atmospheres.

4. A process for the production of acetone team in approximately the propressure of oxyg n within the which'comprises passing a gaseous mixture of acetylene and steam over'a catalyst comprising essentially a plurality of metal oxides, the said 70 catalyst having the partial pressureot oxygen within the range. of 10- to 10* atmospheres. 5 A- process orfthe production of acetone which comprises passing a gaseous mixture of acetylene andsteamover a catalyst comprised 5 essentially oi a heavy metal and an oxide or. a,

vof oxygen within the range atmospheres.

8. A process tor the production of acetone which comprises passing a gaseous mixture of acetylene and steam over a mixture having cata- 20 lytic action and comprising essentially aniron oxide, a,heavy metal carbonate and a metal, the said catalytic mixture having the partial pressure of --10" to 10- atmospheres. i

9. A process for the production of acetone which comprises passinga gaseous mixture of acetylene and steam over a mixture having catalytic action and comprising essentially an iron Y oxide, a light metal carbonate and a metal, the 30 said catalytic mixture having the partial pressure of oxygen within the range of 10-" to 10" atmospheres. v

10. A process for making acetone which comprises passing acetylene and steam,.at tempera- 35 tures within the range 0'! 250 C. to 750 C., over a mixture of a heavy metal oxide and a light metal carbonate, the said mixture having .the partial pressure of oxygen within the range of 10- to 10- atmospheres. 40 11. A process for the production of acetone by reacting acetylene and steam, in thelpresence of a catalytic mixture, comprising the steps oif, pres paring the catalytic mixture from two metal oxides; and bringing a mixtureof one part. of acetylene with five to fifteen parts of steam into contact with said catalytic mixture, at temperatures within the range of, 300 C. to 600 C.; the said catalytic mixture having the partial pressure of oxygen within the range of 10- to 10- atmospheres 12. A process for making acetone which comprises passing a gaseous mixture 0P5 to 15 parts of steam with 1 part of acetylene, in'the presence of iron and at temperatures of from 250 C. to

h i h l sure of oxygen within the range of 10" to 10- eavy metal oxlde one 1 g t meta oxide and one metal, the said mixtures having the partial pressure of oxygen within the range of 10- to 10- atmospheres.

14. A process for producing acetone consisting in passing acetylene and steam, at temperatures between 250 C. and 750 (3., into contact with mixtures of substances which contain one heavy are so compounded: that theiroxygen tension at the temperatures used in the process is near the oxygen partial tension in the reaction mixture containing the oxygen.

15. In theprocess defined in claim 14, starting perature in order to maintain said oxygen tensions in their proper ratio.

16. A process for the production or acetone by reacting acetylene and steam in the presence of a catalytic mixture, consisting in thesteps oi preparing said mixture from iron oxide and an auxiliary catalyst composed of a substance selected from the group consisting of light metal oxides and light metal oxygen compounds which fifteen parts of steam into contact with said catalytic mixture at temperatures within the approximate range of 300 C.-600 0., the said selected proportions of the catalytic mixture being such as to maintain the partial pressure of the oxygen in the catalytic mixture within the approximate range of 10-" to 10-" atmospheres.

17. A process for the production of acetone which comprises passing a gaseous mixture of acetylene and steam over amixture having catalytic action and comprising essentially an oxidic o oxides and a metal; a metal oxide and a metal carbonate; a metal oxide, a metal carbonate and a metal; and a metal oxide and a metal, said 1 catalytic mixture having the partial pressure of oxygen within the range of 10- to 10" atmospheres.

KOLOMAN Rom KARL WESLER. 

